Shoulder Impingement Syndrome (SIS) describes a common injury in which muscles, tendons, or other tissues of the shoulder joint become pinched and inflamed. With impingement comes damage, with damage comes pain, and with all three comes reduced movement, strength, and use of that arm.
So why the heck are we talking about the spine if it’s the shoulder that hurts?! Well, I’ll tell ya. The YouTube song linked above is the key. It’s a very old song, with several versions. And while lacking in exact technical terms, it’s actually true.

Uh… duh, Josh.

I know I know. But think about that more deeply for a moment. If two parts of your body are connected, then the actions of one affect the actions of the other. Our spine is connected to our shoulder via muscles and bones, so a dysfunctioning spine can cause a dysfunctioning shoulder.

The Simpson's- Brother From the Same Planet

So now we can get into the research article describing how spinal manipulations can help reduce symptoms of SIS. (*Side note: manipulation basically means cracking joints. Just like cracking your knuckles. It is not bad for you. Well... unless you do it like Homer did to the right.)

The 2008 article by Boyles et al. describes a study they performed on 56 patients to see how their SIS improved with upper spine manipulation. Essentially: the researchers assessed patients to determine if they had SIS, then measured their pain and function, then performed upper spinal manipulations, and finally took values of their pain and function two days later. In short, their findings showed the patients had significantly less pain and improved function two days after upper spine manipulation. Cool!! But wait… there’s a catch. A recurring theme for The Movement Enhancement Project, and research in general, is the evidence is not as clear as it seems. I will explain further why the evidence in this study is muddy.

This study was actually an exploratory study. An exploratory, or preliminary study is a lot like a rough draft. Typically filled with, holes and mistakes, but an important step on the road to a final draft. So what kind of mistakes and holes did this study have?

Well, the most important one to note is there was no control group. Control groups are those people whom nothing happens to during the study. Hypothetically, in this study, a control group would NOT receive spinal manipulation. They would probably wait in the physical therapy office twiddling their thumbs, and then told to go home. That would suck for them. But, in this study, everyone did receive spinal manipulations, so there was no control group, and no one wasted their day in a PT office reading old magazines from last December.

Control groups are important however, because if the group who got spinal manipulations and the group who twiddled their thumbs in the PT office both improved after two days, then that means the spinal manipulations probably did nothing special. Having pain that randomly disappears after a couple days is a common thing.

So what should you take away from this study? Well… I believe this study provides promising rough draft results to the benefits of performing upper spine manipulations to treat SIS. For the person with SIS, this may directly benefit you in the near future. If more studies find strong evidence stating treating the back will benefit the shoulder, then activities like spinal manipulations, back stretches, and back posture education can now be added to you and your therapist’s repertoire of treatment options.

*On a side note: some other recent developments in research state that with manipulation, the body releases pain-relieving chemicals. So even if the manipulation doesn’t fix the back, at least it triggers the body to release drugs to temporarily relieve pain. COOL. Makes sense though; it always feels good after I manipulate my spine and knuckles.

So, swallow those benefits with a few grains of salt, for the reasons I gave above. There are several holes to the study, and in the interest of your time and boredom, I only gave one example. This is the world of research. It is a lot of questioning what you been told. It makes me feel like a kid again. “Mom, what’s that? Mom, where do babies come from? Why mommy? Why? Why? Why? …

I encourage you to read the study for yourself, and find as many holes as you can. It’s heavy on the terminology, but if you find this fun, then you are a nerd, and can join the party with me and the other research geeks. We’ll be watching Star Trek: TOS. Unfortunately, I cannot provide a full text version of the study, as I would likely be infringing on copyrights. But, I will give you the reference information and the abstract below.

Thanks for scanning with CN III and transmitting through CN II. Peace!

The study was an exploratory, one group pretest/post-test study, with the objective of investigating the short-term effects of thoracic spine thrust manipulations (TSTMs) on patients with shoulder impingement syndrome (SIS). There is evidence that manual physical therapy that includes TSTM and non-thrust manipulation and exercise is effective for the treatment of patients with SIS. However, the relative contributions of specific manual therapy interventions are not known. To date, no published studies address the short-term effects of TSTM in the treatment of SIS. Fifty-six patients (40 males, 16 females; mean age 31.2+/-8.9) with SIS underwent a standardized shoulder examination, immediately followed by TSTM techniques. Outcomes measured were the Numeric Pain and Rating Scale (NPRS) and the Shoulder Pain and Disability Index (SPADI), all collected at baseline and at a 48-h follow-up period. Additionally, the Global Rating of Change Scale (GRCS) was collected at 48-h follow-up to measure patient perceived change. At 48-h follow-up, the NPRS change scores for Neer impingement sign, Hawkins impingement sign, resisted empty can, resisted external rotation, resisted internal rotation, and active abduction were all statistically significant (p<0.01). The reduction in the SPADI score was also statistically significant (p<0.001) and the mean GRCS score=1.4+/-2.5. In conclusion, TSTM provided a statistically significant decrease in self reported pain measures and disability in patients with SIS at 48-h follow-up.